A method for evaluating the radiation emission level of power electronic equipment based on a reverberation chamber

Abstract

The application discloses a method and device for evaluating the radiation emission level of power electronic equipment based on a reverberation chamber, a medium and equipment. The method comprises the following steps: obtaining a reverberation chamber radiation receiving power sample and a transmission coefficient sample; obtaining a radiation power calculation model of the power electronic equipment to be measured, constructing a radiation power function of the power electronic equipment to be measured, obtaining a probability density function of a radiation power estimation value based on the radiation power function of the power electronic equipment to be measured, and obtaining an uncertainty model; evaluating the first radiation emission level of the power electronic equipment to be measured based on the radiation power calculation model and the uncertainty model; and determining the second radiation emission level according to the radiation power function of the power electronic equipment to be measured. The method can accurately describe the statistical distribution characteristics of the electromagnetic field inside the reverberation chamber, quantitatively analyze the influence of the number of independent samples on the measurement uncertainty, and effectively evaluate the statistical characteristics and measurement uncertainty of the radiation emission of the power electronic equipment.

Description

Technical Field

[0001] This application relates to the fields of electromagnetic compatibility testing and reverberation chamber technology, and in particular to a method, apparatus, medium and device for evaluating the radiated emission level of power electronic equipment based on a reverberation chamber. Background Technology

[0002] With the rapid development of power electronics technology, power electronic equipment is increasingly widely used in various fields such as industry, transportation, energy, and household appliances. In actual operation, due to the combined effects of frequent switching of power devices, parasitic effects in internal circuits, and coupling paths between magnetic components, circuits typically generate abundant high-frequency harmonic components. These high-frequency harmonic components radiate outwards as electromagnetic waves through various pathways such as current loops in the circuit, long wires, and heat sinks, interfering with surrounding electronic equipment, affecting its normal operation, and even threatening the reliability and safety of the entire power electronic system. Therefore, accurate and effective radiated emission testing of power electronic equipment to evaluate its electromagnetic radiation characteristics is a necessary prerequisite for ensuring the stable and reliable operation of electronic equipment.

[0003] Currently, domestic standards related to reverberation chambers for testing radiated emissions of electronic equipment, such as GB / T 9254.1, typically only set fixed limits for radiated emissions in specific frequency bands, neglecting the inherent statistical characteristics of reverberation chamber testing and their impact on test results. In reverberation chamber electromagnetic compatibility testing, radiated emission test results exhibit specific statistical characteristics and are not single, fixed values. Furthermore, the size of the independent sample size significantly affects the measurement uncertainty of statistical measurements. Therefore, simply comparing one or a few measurements with fixed limits makes it difficult to accurately assess the actual radiated emission level of the equipment and cannot effectively predict its electromagnetic compatibility performance in real-world operating electromagnetic environments.

[0004] Existing methods for testing and risk assessment of radiated emission reverberation chambers have at least the following shortcomings:

[0005] Current reverberation chamber testing methods for radiated emissions lack accurate statistical theoretical models, making it impossible to conduct systematic analysis of measurement uncertainty and effectively assess the reliability of the results. Furthermore, existing testing methods neglect the inherent statistical characteristics of reverberation chamber testing and the impact of independent sample size on measurement uncertainty, significantly increasing the risk of misjudging whether radiated emissions meet limits. Therefore, using existing methods to assess the radiated emissions of power electronic equipment results in significant deficiencies in both accuracy and reliability, potentially leading to misjudgments of the equipment's electromagnetic compatibility performance and hindering product quality control and design optimization. Summary of the Invention

[0006] The main objective of this application is to provide a method, apparatus, medium, and equipment for assessing the radiated emission level of power electronic equipment based on a reverberation chamber, aiming to solve the technical problem of lacking accurate statistical theoretical models, being unable to conduct systematic analysis of the uncertainty of measurement results, and finding it difficult to effectively assess the reliability of measurement results.

[0007] To achieve the above objectives, this application provides a method for assessing the radiated emission level of power electronic equipment based on a reverberation chamber, comprising: acquiring samples of radiated received power and transmission coefficients in the reverberation chamber; acquiring a radiated power calculation model for the power electronic equipment under test, wherein the power radiation function has a quadratic parameter of the absolute value of the transmission coefficient and a received power parameter, and the quadratic parameter of the absolute value of the transmission coefficient follows an exponential distribution of a first parameter, and the received power parameter follows an exponential distribution of a second parameter; constructing a first random variable and a second random variable using the transmission coefficient samples, the received power samples, and their respective sample numbers; constructing a radiated power function for the power electronic equipment under test based on the first random variable, the second random variable, the first parameter, and the second parameter; obtaining a probability density function of the estimated radiated power based on the radiated power function of the power electronic equipment under test; determining a relative uncertainty model based on the probability density function of the estimated radiated power; assessing a first radiated emission level of the power electronic equipment under test based on the radiated power calculation model and the uncertainty model; determining a confidence upper limit for the radiated emission of the power electronic equipment under test based on the radiated power function of the power electronic equipment under test; and assessing a second radiated emission level of the power electronic equipment under test based on the confidence upper limit.

[0008] Optionally, before constructing the first random variable and the second random variable using the transmission coefficient sample and the received power sample and their respective sample numbers, the method further includes: determining the independence of the transmission coefficient sample and the received power sample based on the magnitude of their respective first-order autocorrelation coefficients.

[0009] Optionally, determining the independence of the transmission coefficient sample and the received power sample based on the magnitude of their respective first-order autocorrelation coefficients includes: calculating the first-order autocorrelation coefficient of the transmission coefficient sample generated by the turntable; calculating the first-order autocorrelation coefficient of the transmission coefficient sample generated by the mechanical stirrer; and determining whether the samples are independent based on the relationship between the first-order autocorrelation coefficient and a preset threshold. Specifically, determining whether a sample is independent means that if the first-order autocorrelation coefficient is less than the preset threshold, the sample is considered independent; conversely, if the first-order autocorrelation coefficient is greater than the preset threshold, the sample is considered not independent.

[0010] Optionally, the step of constructing a first random variable and a second random variable using transmission coefficient samples and received power samples, and their respective sample numbers, and constructing the radiated power function of the power electronic device under test based on the first random variable, the second random variable, the first parameter, and the second parameter includes: obtaining the first random variable based on the product of the sum of squares of the transmission coefficient samples and the sample number of the transmission coefficient samples; obtaining the second random variable based on the product of the sum of the received power samples and the sample number of the received power samples; obtaining a first chi-square distribution based on the product of the first random variable and the first parameter; obtaining a second chi-square distribution based on the product of the second random variable and the second parameter; and rewriting the radiated power calculation model based on the first chi-square distribution and the second chi-square distribution to obtain the radiated power function of the power electronic device under test.

[0011] Optionally, determining the relatively uncertain model based on the probability density function of the radiated power estimate includes: determining the expected value and variance of the radiated power according to the probability density function of the radiated power estimate; and determining the relatively uncertain model based on the expected value and variance of the radiated power.

[0012] Optionally, determining the upper confidence limit of the radiated emission of the power electronic device under test based on its radiated power function includes: obtaining a confidence interval for the radiated power function of the power electronic device under test based on its radiated power function, and determining the upper confidence limit; if the upper confidence limit is less than the recommended limit, then it is determined that the electromagnetic radiation of the power electronic device under test does not exceed the normal level.

[0013] Optionally, the method further includes: if the upper confidence limit is greater than the recommended limit, then it is determined that the electromagnetic radiation of the power electronic equipment under test exceeds the normal level.

[0014] To achieve the above objectives, this application also provides a device for evaluating the radiated emission level of power electronic equipment based on a reverberation chamber, comprising: a sample acquisition module for acquiring radiated received power samples and transmission coefficient samples from the reverberation chamber; a model acquisition module for acquiring a radiated power calculation model of the power electronic equipment under test, wherein the power radiation function has a quadratic parameter of the absolute value of the transmission coefficient and a received power parameter, and the quadratic parameter of the absolute value of the transmission coefficient follows an exponential distribution of a first parameter, and the received power parameter follows an exponential distribution of a second parameter; and a first evaluation module for constructing a first random variable and a received power sample using the transmission coefficient samples and the received power samples, as well as their respective maximum sample sizes. The second random variable is used to construct the radiated power function of the power electronic device under test based on the first and second random variables, as well as the first and second parameters. Based on the radiated power function of the power electronic device under test, a probability density function of the estimated radiated power value is obtained. Based on the probability density function of the estimated radiated power value, a relative uncertainty model is determined. Based on the radiated power calculation model and the uncertainty model, the first radiated emission level of the power electronic device under test is evaluated. The second evaluation module is used to determine the upper confidence limit of the radiated emission of the power electronic device under test based on the radiated power function of the power electronic device under test, and to evaluate the second radiated emission level of the power electronic device under test based on the upper confidence limit.

[0015] To achieve the above objectives, this application also provides a computer-readable storage medium including instructions that, when executed on a computer, cause the computer to perform the reverberation chamber-based method for assessing the radiated emission level of power electronic devices provided in the above embodiments.

[0016] To achieve the above objectives, this application also provides an electronic device, which includes: at least one processor, a memory, and an input / output unit; wherein the memory is used to store a computer program, and the processor is used to call the computer program stored in the memory to execute the reverberation chamber-based power electronic device radiated emission level assessment method provided in the above embodiments.

[0017] This application proposes a method, apparatus, medium, and device for assessing the radiated emission level of power electronic equipment based on a reverberation chamber. The method includes acquiring samples of radiated received power and transmission coefficients from the reverberation chamber; acquiring a radiated power calculation model for the power electronic equipment under test, wherein the power radiation function has a quadratic parameter of the absolute value of the transmission coefficient and a received power parameter, and the quadratic parameter of the absolute value of the transmission coefficient follows an exponential distribution of a first parameter, while the received power parameter follows an exponential distribution of a second parameter; using the transmission coefficient samples, received power samples, and their respective sample numbers, constructing a first random variable and a second random variable; and constructing the radiated power of the power electronic equipment under test based on the first random variable, the second random variable, the first parameter, and the second parameter. The function derives the probability density function of the radiated power estimate from the radiated power function of the power electronic device under test (TEBT), and determines the relative uncertainty model based on the probability density function of the radiated power estimate. It then evaluates the first radiated emission level of the TBT based on the radiated power calculation model and the uncertainty model. Finally, it determines the upper confidence limit of the radiated emission of the TBT based on the radiated power function, and evaluates the second radiated emission level of the TBT based on the upper confidence limit. This allows for an accurate description of the statistical distribution characteristics of the electromagnetic field inside the reverberation chamber and a quantitative analysis of the impact of independently sampled data on measurement uncertainty, thereby achieving an effective assessment of the statistical characteristics and measurement uncertainty of the radiated emission of power electronic devices. Attached Figure Description

[0018] Figure 1 This is a flowchart illustrating an embodiment of the method for assessing the radiated emission level of power electronic equipment based on a reverberation chamber, as provided in this application.

[0019] Figure 2 This is a schematic diagram of the reverberation chamber test environment for radiation emission according to an embodiment of the present invention.

[0020] Figure 3 The first-order autocorrelation coefficient amplitudes of a set of turntables and mechanical stirrers in an embodiment of the present invention are shown.

[0021] Figure 4 These are the measured values ​​of the total radiated power of the two switching power supplies used in the embodiments of the present invention.

[0022] Figure 5 The relationship between the theoretical and empirical relative uncertainty of the radiated power measurement values ​​at 3GHz for the two switching power supplies used in the embodiments of the present invention and the number of independent samples.

[0023] Figure 6(a) shows the comparison results of the radiated emission measurements of the two switching power supplies used in the embodiment of the present invention with the recommended limits when the number of independent samples is 10.

[0024] Figure 6(b) shows the comparison results of the radiated emission measurements of the two switching power supplies used in the embodiment of the present invention with the recommended limits when the number of independent samples is 100.

[0025] Figure 7 This is a structural block diagram of an embodiment of the power electronic equipment radiated emission level assessment device based on a reverberation chamber according to this application.

[0026] The realization of the purpose, functional features and advantages of this application will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0027] It should be understood that the specific embodiments described herein are merely illustrative of this application and are not intended to limit this application.

[0028] The first objective of this invention is to provide a reverberation chamber testing method for radiated emissions. This method can determine the power transfer function within the reverberation chamber and the received power of the receiving antenna when the power electronic device under test (PED) is operating, based on reference tests and tests, thereby achieving accurate measurement of the radiated emissions of the PED. Furthermore, by analyzing the distribution characteristics of the electromagnetic field within the reverberation chamber, this method establishes a theoretical model for measuring the total radiated power of the device based on statistical electromagnetic theory, enabling a more accurate assessment of the device's radiated emission level and providing guidance for the electromagnetic compatibility design of power electronic devices.

[0029] The second objective of this invention is to provide a statistical model for measuring radiated emissions using the reverberation chamber method. This model can accurately describe the statistical distribution characteristics of the electromagnetic field inside the reverberation chamber and quantitatively analyze the impact of independently sampled data on measurement uncertainty, thereby enabling effective evaluation of the statistical characteristics and measurement uncertainty of the equipment's radiated emissions.

[0030] The third objective of this invention is to provide a risk assessment method for radiated emissions of power electronic equipment based on confidence intervals. This method effectively solves the problem of misjudgment caused by insufficient independent sample size in existing testing methods, and can intuitively reflect the uncertainty of radiated emissions of the power electronic equipment under test based on the size of the confidence interval, providing a more reliable basis for the electromagnetic compatibility design and risk management of power electronic equipment.

[0031] Reference Figure 1 The first embodiment of this application provides a method for assessing the radiated emission level of power electronic equipment based on a reverberation chamber. This method may include:

[0032] S10. Obtain samples of radiated received power and transmission coefficients in the reverberation chamber.

[0033] S20. Obtain the radiated power calculation model of the power electronic device under test, wherein the power radiation function has a quadratic parameter of the absolute value of the transmission coefficient and a received power parameter, and the quadratic parameter of the absolute value of the transmission coefficient follows an exponential distribution of the first parameter, and the received power parameter follows an exponential distribution of the second parameter.

[0034] Specifically, steps S10-S20 may include the following execution process:

[0035] Step 1: Connect the reference antenna and the receiving antenna to the two ports of the network analyzer respectively, and change the boundary conditions in the field by mode stirring technology;

[0036] Step 2: At each mixing location in each mode, the network analyzer collects all transport coefficient samples;

[0037] Step 3: Using all the collected transmission coefficient samples, estimate the transmission power value G of the reverberation chamber. REF And complete the reference test according to the following formula:

[0038]

[0039] In the formula η M and η R These are the radiation efficiencies of the receiving antenna and the reference antenna, respectively, Γ. M and Γ R These are the reflection coefficients of the receiving antenna and the reference antenna, respectively. 21,REF It is the transmission coefficient, N REF This is the number of samples in the reference test, and <·> is the sample average operator;

[0040] Step 4: Connect the receiving antenna to the spectrum analyzer and turn on the power electronic device under test;

[0041] Step 5: At each stirring position in the mode, the spectrum analyzer acquires the received power sample P of the power electronic device under test. M ;

[0042] Step 6: Utilize all collected P M Sample, estimate the received power value P of the power electronic device under test. REC The test of the power electronic equipment under test is completed according to the following formula;

[0043]

[0044] In the formula N M This is the number of samples in the test of the power electronic equipment under test;

[0045] Step 7: Calculate the total radiated power of the power electronic device under test based on the transmitted power value, the received power value, and the following formula.

[0046]

[0047] Equation (3) is the radiated power calculation model of the power electronic device under test in this application.

[0048] S30. Using the transmission coefficient samples and received power samples, as well as their respective maximum sample numbers, construct a first random variable and a second random variable. Construct a radiated power function of the power electronic device under test based on the first random variable, the second random variable, the first parameter, and the second parameter. Obtain a probability density function of the estimated radiated power based on the radiated power function of the power electronic device under test. Determine a relative uncertainty model based on the probability density function of the estimated radiated power. Evaluate the first radiated emission level of the power electronic device under test based on the radiated power calculation model and the uncertainty model.

[0049] It should be noted that, in the embodiments of this application, before constructing the first random variable and the second random variable using the transmission coefficient samples and the received power samples and their respective sample numbers, the radiated emission level assessment method for power electronic equipment based on a reverberation chamber proposed in this application may further include the following execution process:

[0050] The independence of the transmission coefficient sample and the received power sample is determined based on the magnitude of their respective first-order autocorrelation coefficients.

[0051] Specifically, in the embodiments of this application, the step of determining the independence of the transmission coefficient sample and the received power sample based on the magnitude of the first-order autocorrelation coefficient of each sample may include the following execution process:

[0052] Obtain the transmission coefficient samples / radiated received power samples for each of the turntable or stirrer;

[0053] Calculate the first-order autocorrelation coefficient of the transmission coefficient sample / radiated received power sample generated by the turntable or stirrer;

[0054] Whether a sample is independent is determined by the relationship between the first-order autocorrelation coefficient and a preset threshold. If the autocorrelation coefficient is less than the preset threshold, the sample is independent; otherwise, the sample is not independent.

[0055] For example, the above steps may include:

[0056] Calculate the first-order autocorrelation coefficient of the turntable or mechanical stirrer sample.

[0057]

[0058] In the formula, S 21(i) represents the i-th turntable or stirrer sample, S 21 (i+1) is S 21 (i) Moving a sample by one position;

[0059] By comparing the magnitude of the first-order autocorrelation coefficient and the threshold value of the samples, it can be verified that the samples collected at different stirring locations are independent of each other.

[0060] Since the statistical model of the power electronic equipment under test is a function of the number of independent samples, the independence between samples must be tested before analyzing the statistical characteristics of power source radiated emissions.

[0061] S40. Determine the upper confidence limit of the radiated emission of the power electronic device under test based on the radiated power function of the power electronic device under test, and evaluate the second radiated emission level of the power electronic device under test based on the upper confidence limit.

[0062] This application provides a method for assessing the radiated emission level of power electronic equipment based on a reverberation chamber. The method, apparatus, medium, and equipment involve: acquiring samples of radiated received power and transmission coefficients from the reverberation chamber; obtaining a radiated power calculation model for the power electronic equipment under test (PEBT), wherein the power radiation function has a quadratic parameter of the absolute value of the transmission coefficient and a received power parameter, and the quadratic parameter of the absolute value of the transmission coefficient follows an exponential distribution of a first parameter, and the received power parameter follows an exponential distribution of a second parameter; constructing a first random variable and a second random variable using the transmission coefficient samples, the received power samples, and their respective maximum sample sizes; constructing a radiated power function for the PEBT based on the first and second random variables and the first and second parameters; obtaining a probability density function of the estimated radiated power based on the radiated power function; determining a relative uncertainty model based on the probability density function of the estimated radiated power; assessing a first radiated emission level of the PEBT based on the radiated power calculation model and the uncertainty model; determining a confidence upper limit for the radiated emission of the PEBT based on the radiated power function; and assessing a second radiated emission level of the PEBT based on the confidence upper limit. It enables accurate description of the statistical distribution characteristics of the electromagnetic field inside the reverberation chamber and quantitative analysis of the impact of the number of independent samples on the measurement uncertainty, so as to achieve effective evaluation of the statistical characteristics and measurement uncertainty of the radiated emission of power electronic equipment.

[0063] In embodiments of this application, step S30 may include the following execution process:

[0064] S301. Based on the product of the sum of squares of the transmission coefficient samples and the number of samples of the transmission coefficient samples, a first random variable is obtained;

[0065] S302. Based on the sum of the received power samples and the product of the number of samples of the received power samples, a second random variable is obtained.

[0066] S303. Based on the product of the first random variable and the first parameter, the first chi-square distribution is obtained;

[0067] S304. Based on the product of the second random variable and the second parameter, the second chi-square distribution is obtained;

[0068] S305. Based on the first chi-square distribution and the second chi-square distribution, rewrite the radiated power calculation model to obtain the radiated power function of the power electronic device under test.

[0069] Specifically, the above steps may include the following execution process:

[0070] According to Hill's plane wave integral theory, the variable X = |S 21,REF | 2 With variable Y=P M They follow an exponential distribution, denoted as X~E(λ). REF ) and Y~E(λ M );

[0071] Define the first random variable R = ∑N REF X i The second random variable G = ∑N M Y i , λ REF R and λ M G follows a sequence of 2N degrees of freedom. REF and 2N M The chi-square distributions are denoted as the first chi-square distribution λ. REF R~χ 2 (2N REF ) and the second chi-square distribution λ M G~χ 2 (2N M The radiated power calculation model P of the power electronic device under test is used. RE Rewrite in the form containing variables R and G

[0072]

[0073] Define a random variable Z = P RE a = λ M / [λ REF η R (1-|Γ R | 2 )],aZ should obey a set of 2N degrees of freedom M and 2N REF The central F distribution is denoted as aZ~F(2N).M ,2N REF ), derive P RE The probability density function is

[0074]

[0075] Obtaining the probability density function of the radiated power estimate based on the radiated power function of the power electronic device under test, and determining the relatively uncertain model based on the probability density function of the radiated power estimate, may include the following execution process:

[0076] The expected value and variance of the radiant power are determined based on the probability density function of the estimated radiant power.

[0077] The relative uncertainty model is determined based on the expected value and variance of the radiated power.

[0078] For example, the above steps may include:

[0079] Calculate the expectation and variance based on the probability density function.

[0080]

[0081] A relative uncertainty model is obtained based on expectation and variance.

[0082]

[0083] In embodiments of this application, step S40 may include the following execution process:

[0084] S401. Based on the radiated power function of the power electronic device under test, obtain the upper confidence limit of the radiated power function of the power electronic device under test;

[0085] S402. If the upper confidence limit is less than the recommended limit, then the electromagnetic radiation of the power electronic equipment under test is determined to be within the normal level.

[0086] For example, the above steps may include the following steps:

[0087] According to the electromagnetic compatibility standard GB / T 9254.1 reverberation chamber test section, the radiated power measurement value P RE The conversion relationship between the electric field strength in free space and the equivalent 3m distance.

[0088] E rad =P RE +97.53dB(11)

[0089] The free space electric field intensity E is obtained rad ;

[0090] Calculate the confidence interval for radiated emissions from the power electronic equipment under test using a statistical model;

[0091] Find the electromagnetic compatibility standard GB / T 9254.1 to obtain the recommended limits for radiated emissions in this frequency range;

[0092] The upper limit of the 95% confidence interval of the calculated radiated power or electric field strength is compared with the standard limit. If the upper limit of the confidence interval is lower than the standard limit, the radiated emission of the power electronic equipment under test is considered to meet the standard requirements; otherwise, there is a risk of exceeding the standard.

[0093] If there is a risk of exceeding the limit, the degree of risk is quantified based on the range of the confidence interval for the portion exceeding the limit. The larger the confidence interval for the portion exceeding the limit, the higher the risk of exceeding the limit, and vice versa.

[0094] Specifically, the statistical model used in the steps to calculate the confidence interval for the radiated emissions of the power electronic equipment under test may include:

[0095] Determine the confidence level 1-α based on the requirements;

[0096] Calculate the radiated power P RE The upper limit α of the confidence interval at a confidence level of 1-α -1 F 1-0.5α (2N M ,2N REF ) and lower limit a - 1 F 0.5α (2N M ,2N REF );

[0097] Based on the F-distribution critical value table, look up the upper and lower limits of the confidence interval to determine the range of the confidence interval.

[0098] Compared with the prior art, the present invention has at least the following beneficial effects:

[0099] 1. This invention provides a radiated emission reverberation chamber test model based on statistical electromagnetic theory, which can accurately describe the statistical distribution characteristics of the electromagnetic field inside the reverberation chamber and quantitatively analyze the influence of the number of independent samples on the measurement uncertainty, thereby realizing the effective evaluation of the statistical characteristics and measurement uncertainty of radiated emission of power electronic equipment.

[0100] 2. This invention provides a radiated emission risk assessment method based on confidence intervals, which can determine whether the radiated emission of a device meets the standard requirements based on the calculated confidence interval of radiated emission, effectively reducing misjudgments caused by insufficient independent sample size, and providing a more scientific decision-making basis for the electromagnetic compatibility design and risk management of power electronic equipment.

[0101] 3. This invention applies statistical electromagnetic theory to the reverberation chamber test of radiated emissions from power electronic equipment, enabling a quantitative assessment of the statistical characteristics and measurement uncertainty of the test results. This provides a theoretical basis for the analysis of reverberation chamber test results and helps promote the application and dissemination of statistical electromagnetic theory in other reverberation chamber tests.

[0102] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments.

[0103] A schematic diagram of the reverberation chamber used in the embodiments of the present invention is shown below. Figure 2 As shown. The reverberation chamber measures 1.50m × 1.44m × 0.92m and contains two mechanical stirrers and a turntable with a height-adjustable antenna bracket. The reference antenna is a cone antenna, and the receiving antenna is a standard horn antenna. The receiving antenna is mounted on a bracket on the bottom of the reverberation chamber, while the reference antenna is mounted on a bracket on the turntable, offset 20cm from the turntable center (turntable diameter 60cm). The power electronic device under test (PED) is connected to the load and placed on another bracket on the turntable, also offset 20cm from the turntable center. During reference testing, the reference antenna and receiving antenna are connected to two ports of the network analyzer, respectively. During testing of the PED, the receiving antenna is connected to a port of the spectrum analyzer. The PED is a commercially available switching power supply; the load is a purely resistive heating resistor with a resistance of 25 ohms.

[0104] The test frequency band of this embodiment is 1GHz to 4GHz. The stirrer and turntable rotate independently, with 10 different stopping positions per revolution, resulting in 100 stirring positions in a single test. The spatial position of the receiving antenna remains unchanged throughout the test. Since calculating the relative uncertainty of radiated emissions requires multiple independent radiated emission measurement samples, this paper employs a 9-point test method to repeatedly perform the above experiment. The 9-point test method involves adjusting the support brackets for the power electronic device under test (DUT) and the reference antenna, distributing them at three different vertical heights, with the distance between each height greater than half the wavelength of the lowest test frequency. At each height, the DUT and the reference antenna are oriented towards three mutually perpendicular directions.

[0105] The calculation results of the first-order autocorrelation coefficient amplitudes of two switching power supplies, power supply A and power supply B, in this embodiment of the invention are as follows: Figure 3As shown, the threshold value is [value missing]. It can be observed that the values ​​are generally below the threshold across the entire frequency band. Therefore, the 100 samples obtained within the 1GHz-2GHz range can be considered independent of each other. Power supply A is from Mean Well, with an input of 220V-50Hz AC and an output of 24V DC, with a rated power of 76.8W. Power supply B is from Hetian Shengming, with an input of 220V-50Hz AC and an output of 12V DC, with a rated power of 50.4W.

[0106] The radiated emission test results of two switching power supplies in this embodiment of the invention are as follows: Figure 4 As shown in the diagram, since the output voltage of power supply A is twice that of power supply B, under the same load, the output power of power supply A is four times that of power supply B. The results show that the radiated power of power supply A is significantly higher than that of power supply B, indicating that devices with higher output power typically generate stronger electromagnetic radiation during operation.

[0107] The theoretical and empirical relative uncertainty of the radiated power measurement values ​​of the two switching power supplies used in this embodiment of the invention at 3GHz varies with the number of independent samples as follows: Figure 5 As shown, regardless of the number of independent samples or the output power of the power electronic device under test, the theoretically calculated value of the relative uncertainty is in high agreement with the empirical value obtained from actual measurements. This phenomenon strongly supports the accuracy and reliability of the theoretical uncertainty model.

[0108] This invention compares the radiated emission measurements of two switching power supplies with 10 and 100 independent samples, and displays the corresponding 95% confidence intervals, as shown in Figure 6. When the number of independent samples is 10, the 95% confidence interval is wide, indicating greater measurement uncertainty. When the number of independent samples increases to 100, the confidence interval narrows significantly, indicating that the measured values ​​are more stable and reliable. This demonstrates that a smaller number of independent samples easily leads to measured values ​​deviating from the true values. Therefore, the impact of the number of independent samples must be considered when evaluating the radiated emissions of power electronic equipment. This invention innovatively compares the upper limit of the 95% confidence interval with a reference limit, enabling a more reliable assessment of radiated emissions and reducing the risk of misjudgment due to insufficient independent samples.

[0109] refer to Figure 7 Based on the above embodiments, this application also provides a power electronic equipment radiated emission level assessment device based on a reverberation chamber. The power electronic equipment radiated emission level assessment device 1000 includes:

[0110] The model acquisition module 1001 is used to acquire the radiated power calculation model of the power electronic device under test, wherein the power radiation function has a quadratic parameter of the absolute value of the transmission coefficient and a received power parameter, and the quadratic parameter of the absolute value of the transmission coefficient follows an exponential distribution of the first parameter, and the received power parameter follows an exponential distribution of the second parameter.

[0111] The first evaluation module 1002 is used to construct a first random variable and a second random variable using transmission coefficient samples and received power samples and their respective maximum sample numbers, construct a radiated power function of the power electronic device under test based on the first random variable and the second random variable, as well as the first parameter and the second parameter, obtain a probability density function of the radiated power estimate based on the radiated power function of the power electronic device under test, determine a relative uncertainty model based on the probability density function of the radiated power estimate, and evaluate the first radiated emission level of the power electronic device under test based on the radiated power calculation model and the uncertainty model.

[0112] The second evaluation module 1003 is used to determine the confidence upper limit of the radiated emission of the power electronic device under test based on the radiated power function of the power electronic device under test, and to evaluate the second radiated emission level of the power electronic device under test based on the confidence upper limit.

[0113] Based on the above embodiments, this application also provides a computer-readable storage medium including instructions that, when executed on a computer, cause the computer to perform the reverberation chamber-based method for assessing the radiated emission level of power electronic equipment provided in any of the above embodiments.

[0114] Based on the above embodiments, this application also provides an electronic device, the electronic device comprising: at least one processor, a memory, and an input / output unit; wherein, the memory is used to store a computer program, and the processor is used to call the computer program stored in the memory to execute the method for evaluating the radiated emission level of power electronic equipment based on a reverberation chamber provided in any of the above embodiments.

[0115] The above are merely preferred embodiments of this application and do not limit the patent scope of this application. Any equivalent structural or procedural transformations made using the content of this application's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of this application.

Claims

1. A method for assessing the radiated emission level of power electronic equipment based on a reverberation chamber, characterized in that, include: Obtain samples of radiated received power and transmission coefficients from the reverberation chamber; A radiated power calculation model for the power electronic device under test is obtained, wherein the radiated power calculation model has a quadratic parameter of the absolute value of the transmission coefficient and a received power parameter, and the quadratic parameter of the absolute value of the transmission coefficient follows an exponential distribution of a first parameter, and the received power parameter follows an exponential distribution of a second parameter. Using transmission coefficient samples and received power samples, along with their respective sample numbers, a first random variable and a second random variable are constructed. Based on the first random variable, the second random variable, the first parameter, and the second parameter, a radiated power function of the power electronic device under test is constructed. Based on the radiated power function of the power electronic device under test, a probability density function of the estimated radiated power value is obtained. Based on the probability density function of the estimated radiated power value, a relative uncertainty model is determined. Based on the radiated power calculation model and the relative uncertainty model, the first radiated emission level of the power electronic device under test is evaluated. The step of constructing a first random variable and a second random variable using transmission coefficient samples, received power samples, and their respective sample numbers, and constructing the radiated power function of the power electronic device under test based on the first random variable, the second random variable, the first parameter, and the second parameter includes: The first random variable is obtained by multiplying the sum of squares of the transmission coefficient samples and the number of samples of the transmission coefficient samples. The second random variable is obtained by multiplying the sum of the received power samples and the number of samples of the received power samples. The first chi-square distribution is obtained based on the product of the first random variable and the first parameter; The second chi-square distribution is obtained based on the product of the second random variable and the second parameter; The radiated power calculation model is rewritten based on the first chi-square distribution and the second chi-square distribution to obtain the radiated power function of the power electronic device under test; The confidence upper limit of the radiated emission of the power electronic device under test is determined based on the radiated power function of the power electronic device under test, and the second radiated emission level of the power electronic device under test is evaluated based on the confidence upper limit.

2. The method for assessing the radiated emission level of power electronic equipment based on a reverberation chamber as described in claim 1, characterized in that, Before constructing the first and second random variables using transmission coefficient samples, received power samples, and their respective sample numbers, the method further includes: The independence of the transmission coefficient sample and the received power sample is determined based on the magnitude of their respective first-order autocorrelation coefficients.

3. The method for assessing the radiated emission level of power electronic equipment based on a reverberation chamber as described in claim 2, characterized in that, The step of determining the independence of the transmission coefficient sample and the received power sample based on the magnitude of their respective first-order autocorrelation coefficients includes: Obtain the transmission coefficient samples / radiated received power samples for each of the turntable or stirrer; Calculate the first-order autocorrelation coefficient of the transmission coefficient sample / radiated received power sample generated by the turntable or stirrer; Whether a sample is independent is determined by the relationship between the first-order autocorrelation coefficient and a preset threshold. If the autocorrelation coefficient is less than the preset threshold, the sample is independent; otherwise, the sample is not independent.

4. The method for assessing the radiated emission level of power electronic equipment based on a reverberation chamber as described in claim 1, characterized in that, The determination of the relatively uncertain model based on the probability density function of the radiated power estimate includes: The expected value and variance of the radiant power are determined based on the probability density function of the estimated radiant power. The relative uncertainty model is determined based on the expected value and variance of the radiated power.

5. The method for assessing the radiated emission level of power electronic equipment based on a reverberation chamber as described in claim 1, characterized in that, Determining the upper confidence limit of the radiated emission of the power electronic device under test based on its radiated power function includes: Based on the radiated power function of the power electronic device under test, the confidence interval of the radiated power function of the power electronic device under test is obtained; If the upper confidence limit is less than the recommended limit, then the electromagnetic radiation of the power electronic equipment under test is determined to be within the normal level.

6. The method for assessing the radiated emission level of power electronic equipment based on a reverberation chamber as described in claim 1, characterized in that, The method further includes: If the upper confidence limit is greater than the recommended limit, the electromagnetic radiation of the power electronic equipment under test is judged to exceed the normal level.

7. A device for evaluating the radiated emission level of power electronic equipment based on a reverberation chamber, characterized in that, include: The sample acquisition module is used to acquire samples of radiated received power and transmission coefficients in the reverberation chamber. The model acquisition module is used to acquire the radiated power calculation model of the power electronic device under test. The radiated power calculation model has a quadratic parameter of the absolute value of the transmission coefficient and a received power parameter. The quadratic parameter of the absolute value of the transmission coefficient follows an exponential distribution of the first parameter, and the received power parameter follows an exponential distribution of the second parameter. The first evaluation module is used to construct a first random variable and a second random variable using transmission coefficient samples and received power samples and their respective sample numbers; construct a radiated power function of the power electronic device under test based on the first random variable, the second random variable, the first parameter, and the second parameter; obtain a probability density function of the estimated radiated power based on the radiated power function of the power electronic device under test; determine a relative uncertainty model based on the probability density function of the estimated radiated power; and evaluate the first radiated emission level of the power electronic device under test based on the radiated power calculation model and the relative uncertainty model. The step of constructing a first random variable and a second random variable using transmission coefficient samples, received power samples, and their respective sample numbers, and constructing the radiated power function of the power electronic device under test based on the first random variable, the second random variable, the first parameter, and the second parameter includes: The first random variable is obtained by multiplying the sum of squares of the transmission coefficient samples and the number of samples of the transmission coefficient samples. The second random variable is obtained by multiplying the sum of the received power samples and the number of samples of the received power samples. The first chi-square distribution is obtained based on the product of the first random variable and the first parameter; The second chi-square distribution is obtained based on the product of the second random variable and the second parameter; The radiated power calculation model is rewritten based on the first chi-square distribution and the second chi-square distribution to obtain the radiated power function of the power electronic device under test; The second evaluation module is used to determine the confidence upper limit of the radiated emission of the power electronic device under test based on the radiated power function of the power electronic device under test, and to evaluate the second radiated emission level of the power electronic device under test based on the confidence upper limit.

8. A computer-readable storage medium, characterized in that, It includes instructions that, when executed on a computer, cause the computer to perform the method for assessing the radiated emission level of power electronic equipment based on a reverberation chamber as described in any one of claims 1 to 6.

9. An electronic device, characterized in that, The electronic device includes: At least one processor, memory, and input / output unit; The memory is used to store computer programs, and the processor is used to call the computer programs stored in the memory to execute the method for evaluating the radiated emission level of power electronic equipment based on a reverberation chamber according to any one of claims 1 to 6.

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